基于“高分四号”卫星数据的水体提取效果评价

"高分四号"卫星具有静止轨道卫星高时间分辨率和中高空间分辨率的特点,可以实现对水体面积及变化的大范围实时监测,有效支撑洪涝灾害应急救助工作。为了验证其对水体面积及其变化的监测能力,文章分别利用区域生长法和水体指数法,在开展全国水体面积变化监测基础上,针对与同期"高分一号"卫星16m分辨率多光谱相机及美国Terra卫星的中分辨率成像光谱仪数据等卫星的监测结果展开对比,结果显示,与其他极轨卫星监测结果相比,"高分四号"卫星可以有效开展水体面积及变化监测。但是,鉴于"高分四号"卫星50m像元分辨率,相比更高分辨率遥感影像的水体提取结果,"高分四号"卫星数据提取的水体外部轮廓较为粗糙。在针对规模较小洪涝灾害监测方面可能存在一定误差,仍然需要再进一步开展评价。     

陆面水体监测中卫星遥感数据适宜性评价方法研究

作为地球表层三大地物(水、土壤、植物)之一,水既是人类生存和发展的最基本资源,又是影响全球气候变化的最活跃因子之一.充分利用遥感技术对地面水体进行动态监测,是水资源-环境-灾害系统研究的重要内容,也是遥感应用研究的重点和难点.近20年来,运用遥感技术监测水域面积、水位以及蓄水量的动态变化,使得陆地水体的动态监测具有广阔的前景,卫星遥感数据在大范围水体监测中已开始发挥重要作用.     

一种遥感影像快速计算水面率的方法

为了有效去除阴影噪声对遥感影像水体提取的干扰,快速准确计算大区域范围内的水面率,本文提出基于GF6（高分六号卫星）影像,利用UWI（Urban Water Index,城市水体指数）并结合FROM-GLC10（Finer Resolution Observa-tion and Monitoring of Global Land Cover 10,全球陆地覆盖精细化观测与监测10）数据,通过求交计算和小碎斑删除实现水体提取结果的精细化,有效消除了阴影等噪声对水体提取的干扰,实现水面率的快速计算。本文选择中山市作为试验区,试验区域范围广、地物背景复杂,综合对比本文算法、NDWI（Normalized Water Index,归一化水体指数）算法和TSUWI（Two-Sted Urban Water Index,城市二类水体指数）算法,从定性与定量角度分析,结果表明：本文算法提取的水体连续完整、漏提和误提较少,可有效去除阴影、建筑、道路等噪声干扰,在总体精度、Kappa系数、错分误差、漏分误差等指标均取得了较好结果。利用UWI与FROM-GLC10数据相结合计算水面率具有可行性,为工程化、大面积、快速计算水面率提供了一种新的思路。     

FY-3卫星洪涝灾害监测应用

对利用风云三号(FY-3)卫星数据对洪涝灾害监测进行了研究。给出了用FY-3卫星中分辨率成像仪(MERSI)和可见光红外扫描辐射计(VIRR)对薄云下和薄雾覆盖的水体判识的原理,以及洪涝信息检测中水体最大淹没面积和淹没时间信息的获取方法。给出了用FY-3卫星微波成像仪(MWRI)通过微波指数法反演洪涝信息的方法,可进行连续、全天候的大范围洪涝灾情监测。2011、2016年由其他卫星获得的洪涝水体信息表明:风云卫星的洪涝水体监测精度可达90%以上,甚至优于EOS卫星的MODIS和NOAA卫星的AVHRR的精度。近年来,风云卫星在国内外洪涝灾害等重大灾害监测评估中发挥了重要作用,改变了业务上以国外卫星资料为主进行洪涝灾害监测的局面,同时也提升了FY-3卫星在国际上的地位。展望了我国风云卫星在洪涝监测中的发展方向,指出随着风云卫星遥感技术的不断发展,洪涝灾害监测评估精度将会提高,为洪涝灾害防灾减灾提供更科学准确的决策依据。     

高分四号卫星在溃决型洪水灾害监测评估中的应用

高分四号卫星具有响应速度快、重复观测周期短等优势,是监测溃决型洪水发展变化状况的有效手段。以江西省鄱阳县河堤溃口引发的洪水灾害为例,将灾区灾后多时相的高分四号卫星连续监测图像与灾前高分一号卫星图像结合,提出空间位置关系约束条件下的溃决型洪水范围提取方法。通过构建人口评估模型,实现受灾人口的快速估算。应用结果表明:高分四号卫星能及时监测突发性溃决型洪水,并能根据实际需求实现对灾区的连续监测;基于高分四号卫星图像的洪水范围提取和受灾情况评估方法,简便易行、准确性高,可用于溃决型洪水范围及其变化的监测评估。根据溃决型洪水灾害监测评估的实际应用需求,从多种卫星的组合观测、地球静止轨道卫星性能指标提升等方面提出了高分四号卫星应用和后续卫星研制建议。     

江苏省CBERS-1卫星红外数据应用示范研究评价

文章对CBERS -1卫星IRMSS数据从空间分辨率、几何精度、噪声等方面作了分析评价 ,选取典型的南京地区、洪泽湖作为示范应用区 ,经过几何精纠正后的IRMSS数据进行不同地物在不同波段上的光谱采样分析 ,进行了城市信息与湖泊信息提取实验 ,效果较好 ,对南京辖区和洪泽湖的形态特征、环境因素、动态变迁等方面作了分析研究 ,从图像上可以清晰地看出南京辖区水体、城建和交通以及郊区的农林状况、洪泽湖河口淤积、岸边污染的情况。总之 ,CBERS-1卫星IRMSS数据可用 ,质量较好 ,达到了设计要求 ,有广阔的应用前景。     

基于GEE的廊坊城区黑臭水体的遥感监测

本文利用GEE(Google Earth Engine)平台中的多源遥感数据与随机森林分类器对廊坊城区黑臭水体进行了提取。研究结果表明：（1）光学遥感数据中的红光、绿光和蓝光波段可以准确反映水色信息,而雷达后续散射数据可以在一定程度上反映污水表面的几何信息,融合光学与微波的多源遥感特征可以更加准确地的提取黑臭水体信息。（2）随机森林分类器的训练精度达到96.7%,分类精度达到了93.7%,可以基本满足对城市黑臭水体监测的要求。（3）在非黑臭水体的岸边、干涸区域、桥梁等会出现分类错误,这些分类错误是由多源遥感数据的在黑臭和非黑臭水体属性特征空间上的重叠造成的,加大样本点的数量与更多特征属性的选择将有助于提高这部分区域的分类精度。（4）免费的数据与算法可以为环保相关部门低成本定期监测城区黑臭水体提供切实可行、廉价的解决方案。     

江苏省CBERS—1卫星红外数据应用示范研究评价

文章对CBERS－1卫星IRMSS数据从空间分辨率、几何精度、噪声等方面作了分析评价，选取典型的南京地区、洪泽湖作为示范应用区，经过几何精纠正后的IRMSS数据进行不同地物在不同波段上的光谱采样分析，进行了城市信息与湖泊信息提取实验，效果较好，对南京辖区和洪泽湖的形态特征、环境因素、动态变迁等方面作了分析研究，从图像上可以清晰地看出南京辖区水体、城建和交通以及郊区的农林状况、洪泽湖河口淤积、岸边污染的情况。总之，CBERS－1卫星IRMSS数据可用，质量较好，达到了设计要求，有广阔的应用前景。     

环境减灾-1A、1B卫星光学载荷在轨运行情况分析

环境减灾-1A、1B卫星于2008年9月6日发射升空,至2013年7月20日,2颗卫星的4台宽覆盖多光谱CCD相机、1台超光谱成像仪(HSI)和1台红外相机(IRS)已在轨稳定工作近5年,共获取超过61万景2级地面遥感图像数据。文章对在轨运行的光学载荷遥测参数进行了统计和分析,结果表明:DC/DC电压遥测变化量不超过5%,关键光机部位温度遥测变化量小于2.25℃,转动部件电压和电流遥测变化量小于1%,遥测参数均在设计范围内,显示光学载荷在轨稳定正常工作。最后,综合分析了光学载荷图像数据应用情况,分析表明:光学载荷图像数据具有较强的地物影像分类、提取和分辨能力,与国外同类卫星比较,水体识别符合度达到90%以上,旱情分级符合度大于66%,光谱分辨率达到5nm,积雪范围提取精度达到90%以上,在各类应用领域发挥了较大的效能。     

基于遥感的汶川震区水体快速提取

＂5.12＂汶川8.0级地震后发生大量滑坡、泥石流,河流部分阻断,形成一系列堰塞湖,急需快速提取水体信息,为救援提供重要依据。本文以震后北川县城为例,利用LBV变换与NDVI（归一化植被指数）图像结合模型对研究区水体进行提取,对＂福卫二号＂影像进行LBV变换,确定B阈值,并提取NDVI指数,两者求交集得到水体影像。该模型理论依据充分可靠,计算机容易实现,具有较高的准确度,可以将水体与低密度覆盖的水植混合体区分开,提取结果符合实际情况,提取速度快,完全能满足灾害背景参数8h内提取的要求。     

燃气发生器喷注器内氧腔三维流动分析

采用计算流体力学方法数值模拟了某型液体火箭发动机燃气发生器氧腔内部流动,详细分析了氧腔内部的三维流动特性。从压力分布等方面分析了造成喷嘴流量分布不均匀的原因,并据此对发生器结构进行了改进,结果表明喷嘴流量分配均匀性得到了明显改善。     

Ariane transfer vehicle in service of man in orbit

The Ariane transfer vehicle (ATV), an Ariane 5 borne, unmanned propulsion vehicle, is designed to transport the logistics needed to resupply the International Space Station (ISS) and the man tended free flyer (MTFF) step 2 with pressurized and unpressurized cargo and to dispose the waste. The ATV is an expendable vehicle and is disposed of by a safe atmospheric burn up. In accordance with the AR5 schedule it should be operational in 1996 for missions toward ISS and beyond the year 2000 for MTFF 2 missions. The main constituents of the proposed ATV are the modified AR5 third stage L5, an upgraded VEB steering the launcher as well as the ATV and the P/L-adaptor providing mechanical and umbilical links to the payload. The mechanical part of the RVD-kit will be placed on the payload-module, the main RVD sensors are located on the adaptor and the needed computer intelligence will be integrated on the VEB. To minimize the development, and recurring costs, the ATV concept fully complies to the idea of maximum use of existing hardware and software, mainly from the AR5, Hermes and Columbus programs thus minimizing development and recurring costs. The ATV is compatible to ISS, MTFF and OMV and is able to transport logistic modules compatible with NSTS and U.S.-expendable launchers.     

Entrapment of bacteria in fluid inclusions in laboratory-grown halite

Cells of the bacterium Pseudomonas aeruginosa, which were genetically modified to produce green fluorescent protein, were entrapped in fluid inclusions in laboratory-grown halite. The bacteria were used to inoculate NaCl-saturated aqueous solutions, which were allowed to evaporate and precipitate halite. The number, size, and distribution of fluid inclusions were highly variable, but did not appear to be affected by the presence of the bacteria. Many of the inclusions in crystals from inoculated solutions contained cells in populations ranging from two to 20. Microbial attachment to crystal surfaces was neither evident nor necessary for entrapment. Cells occurred exclusively within fluid inclusions and were not present in the crystal matrix. In both the inclusions and the hypersaline solution, the cells fluoresced and twitched, which indicates that the bacteria might have remained viable after entrapment. The fluorescence continued up to 13 months after entrapment, which indicates that little degradation of the bacteria occurred over that time interval. The entrapment, fluorescence, and preservation of cells were independent of the volume of hypersaline solution used or whether the solutions were completely evaporated prior to crystal extraction. The results of this study have a wide range of implications for the long-term survival of microorganisms in fluid inclusions and their detection through petrography. The results also demonstrate the preservation potential for microbes in hypersaline fluid inclusions, which could allow cells to survive harsh conditions of space, the deep geologic past, or burial in sedimentary basins.     

Inflection points in the development of energy in space

Basing his comments around a report on the Space Power Systems 1997 conference, ‘Energy and Space for Humanity’, held in Montreal, 24-28 August 1997, Richard Boudreault describes the progress made in getting the concept of power from space accepted by the terrestrial utilities. Increasing worries about the sustainability of current power sources together with deregulation of power distribution make space power more attractive. However, the high cost of access to space is a barrier, though this is starting to fall.     

Power law distribution in statistics of failures in operation of spacecraft onboard equipment

The possibility of using the statistics of recurrence time for extreme events is studied in this paper having in mind the problems of control and prediction of failures in spacecraft operation. The information about failures onboard satellites of various types presented by the US National Geophysical Data Center was analyzed. It was found that the probability density of recurrence intervals followed a power law of the Pareto type with an index equal to 2.3. The obtained result is consistent both with the theory of normal catastrophes and with the principle of self-organization of criticality for metastable active heterogeneous environment. A practical consequence of the obtained result consists in the fact that predictions of these extreme events should not rely on traditional models with the second-order Pearson statistics. To make predictions, the models are necessary that take into account the power law distribution of recurrence intervals for failures on satellites. The failures should be considered in these models as extreme events connected with manifestation of the space environment factors.     

航空航天复合材料非热压罐成型研究进展

介绍了复合材料非热压罐成型的研究进展,包括非热罐成型用的树脂体系、预浸料技术、纤维自动铺放技术以及双真空袋成型工艺等,探讨了非热压罐技术的发展现状和前景。     

航天科技集团公司2006年工作要点

中国航天科技集团公司党组一号文件部署了集团公司2006年九个方面的工作要点。现将这九个要点归纳为四大板块,同时将每个要点的详细内容逐一呈现,以便读者学习、领会与掌握。     

VFW技术在发动机试验系统多余物检测中的应用

论述了发动机试验工艺系统多余物产生机理、多余物控制的基本要求,提出了一种基于VFW技术建立的便携式简易内窥镜多余物图像检测系统.主要对软件设计思路进行了论述,并详细介绍了该系统在现有试车台工艺系统多余物控制中的应用,该技术的应用实现了多余检测过程的数字化管理,提高了试验系统单元部件多余物检测效率.并使检测手段便捷化.     

Achievements of CASC in 2016

<正>2016 was an important year for China’s space industry.October 8,2016 marked the 60th anniversary of the creation of the nation’s space industry.Through 60 years’unremitting effort of generations of space personnel,China’s space industry develops and grows stronger and has achieved splendid results representing by"two bombs and one satellite",manned spaceflight and lunar exploration,which greatly enhanced the national strengths in defense,economy,science and technology